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Author Topic:   Gash in Hull of 13 ft
cvsa78 posted 11-12-2001 01:09 PM ET (US)   Profile for cvsa78   Send Email to cvsa78  
My 13 ft popped off the bunk board while on the trailer and created a gash on the bottom of the hull. Any Idea's on how to repair a older 1970 whaler, myself.


JBCornwell posted 11-12-2001 01:16 PM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
Does the gash go all the way through to the foam?

I have done this before, but Let's see what real experts have to say first.

Red sky at night. . .
JB :)

cvsa78 posted 11-12-2001 01:27 PM ET (US)     Profile for cvsa78  Send Email to cvsa78     
Yes, the gash is all the way through. If I press down, it flexes and it's deep.

Do I have to wait for the foam to dry out before repairing.


Arch Autenreith posted 11-12-2001 02:06 PM ET (US)     Profile for Arch Autenreith  Send Email to Arch Autenreith     
I have done a very similar repair after hitting a dead head. Just get West Systems manuals (3 @ $3 each or you can download from thier site) and decide which method to use. The one that might make sense is to drill evenly-spaced holes, fill with epoxy from syringe and tape closed. Grind off gel coat and re-glass. Thier explaination is much better of course. It worked perfectly for me.
Good luck. It's not such a bad job once you get past the shock of seeing the damage.
cvsa78 posted 11-12-2001 02:21 PM ET (US)     Profile for cvsa78  Send Email to cvsa78     
Hi Arch

Do you mean west marine? If I flood the gash with fiberglass resin and put a piece of glass over and glass that in. Would this work also?


Arch Autenreith posted 11-12-2001 02:39 PM ET (US)     Profile for Arch Autenreith  Send Email to Arch Autenreith

I could try explaining 'til I am blue but I can't do as well as them. Plan on spending a couple hours reading the manuals and thinking about it before doing anything. If the instructions are not adequate call them direct. They were very helpful and nice. They even returned my call!


Arch Autenreith posted 11-12-2001 02:46 PM ET (US)     Profile for Arch Autenreith  Send Email to Arch Autenreith     
Oops...I'm sure you would have figured it out but more accurately it's:

cvsa78 posted 11-12-2001 02:55 PM ET (US)     Profile for cvsa78  Send Email to cvsa78     
Thanks, I'll look into it.


Tom W Clark posted 11-12-2001 03:11 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

Let me quote you from official Boston Whaler, Inc. repair instructions published in April of 1994:

Large Structural Repairs (Rebuilding of crushed or ripped away sections)

In brief, repairs are accomplished by fitting blocks of foam into the damaged areas, carving to original shape and covering with the appropriate thickness of fiberglass. Finally the fiberglass is ground and sanded smooth and sprayed with colored resin for finish.

Use only polyurethane foam since it is not affected by resin used in “laying-up” the fiberglass for the covering “skin” (styrofoam will dissolve in contact with resin). Polyurethane foam is obtainable in ready made blocks or in two-part liquid which when mixed in the recommended proportions and poured into the cardboard box of the required size will yield a good carving foam in a short time. Two pound per cubic foot density is recommended in either case. (Isocyanate Products’ Isofoam PW-2 or PPG’s 6403/6564 are two good foams available in small quantities).

If several blocks must be used, fasten them together with toothpicks, pencils, or even splinters of wood forced into each foam block. Do not glue-up blocks of foam to the required size. The glue line (since it is harder) does not sand down as easily as the foam thereby leaving a high spot or ridge. It becomes very difficult to obtain a smooth looking surface. It is not necessary to achieve a complete absence of voids. The main purpose is to have a surface on which to lay new glass.

After carving and sanding foam to shape (foam should be lower than the surrounding fiberglass skin by the thickness of the skin) undercut and taper the surrounding skin by fashioning a hook from an old file or piece of heavy wire, and cleaning the foam away from under the skin about 1” and tapering the skin with a disc grinder to a knife edge at the hole starting about 2” away all around the hole.

Catalyze general purpose resin for about a 1/2 hour gel time and then mix in chopped fibers to create a stiff mash. Stuff this mash all around the repair under the existing skin.

Before mash is hard, cover repair and taper original skin with no less than two layers of 2 oz. fiberglass may on large “panel” areas and no less than four layers on areas of severe wear.

Finally, grind and sand the fiberglass to a smooth surface flush with the original skin and “paint” the entire area with catalyzed gelcoat. Wet sand to desired finish, using progressively finer grades of sand paper. To duplicate the original finish, wind up with auto buffing compound.

NOTE: If you sand through the gelcoat during the previous step, scuff the area with 100 grit paper and repeat.

I have edited the above for ease of reading. The complete instructions are more extensive and have specific recommendations for different types of repairs. They also include illustrations not included here for obvious reasons.

lhg posted 11-12-2001 03:42 PM ET (US)     Profile for lhg    
I would have to vote in favor of the BW official instructions as quoted by Tom Clark.

I believe the West System of hull repairs is not appropriate for Whaler's unique hull construction.

There is so much interest in this subject that I would like to see JimH add this to the site reference section.

bigz posted 11-12-2001 04:31 PM ET (US)     Profile for bigz    

Well before you start cutting out foam, the question is do you think it is destroyed or just damp? How wide and long is the gash? Deep is relative term -- did you "carve" out any foam or is just fiberglass mat cut and some foam exposed.

The reason for all the questions is that if as you say a "gash" and it just tore through the fiberglass the need to remove foam might not be at all necessary.

This doesn't at least the way your describing it come any where close to what Whaler refers are Large Structural repairs --- hopefully this will be the case -- and frankly no offense to Whaler there are numerous other methods but none are a snap.


bigz posted 11-12-2001 04:43 PM ET (US)     Profile for bigz    
Larry, respectfully disagree when you say repair for a Whaler hull is unique. It is just like any other fiberglass cored structure that use foam or say balsa -- nothing unique about the basics --

Jim has a good section on repairing minor problems and really don't think this site needs much more.
Plenty of references around from technical books to websites which specialize in fiberglass repairs --- we even have numerous post on major restorations right on the forum -- anyway just my opinion Tom

cvsa78 posted 11-12-2001 04:57 PM ET (US)     Profile for cvsa78  Send Email to cvsa78     
The gash is about as wide as a matchbook folded folded twice about 8 inches long. I do not know if the foam is damaged. It did get wet though.


lhg posted 11-12-2001 04:57 PM ET (US)     Profile for lhg    
Tom, for your reference, I'll drop a copy of Whaler's official hull repair instructions in the mail to you. Let me know what you think.
Arch Autenreith posted 11-12-2001 08:24 PM ET (US)     Profile for Arch Autenreith  Send Email to Arch Autenreith     
I have done 2 relatively major and several minor repairs on my Whaler but many others repairs on my own boats over the years . This by no means makes me an expert, and far from it, actually, but here’s what my current thinking is.

Several years ago Larry faxed me the BW repair manual. I read and studied it then proceeded to do as they (BW) had suggested. It involved cutting out the damaged area, tapering the edges, gouging the foam from under the edges, making ‘mash’ (as BW called it) and mashing the mash (lol) under the lip and finally finishing off with new glass using progressively larger mats. Replacing foam was additional work but oftentimes unless you have a really big crushing blow or rip, that wasn’t necessary.

I had already cut out the damaged area when I called Gougeoun Bros. and told them what I was doing and asked what material should I use to make the mash to mix with the epoxy? They asked why I was going to, in effect, put a ‘hard doughnut’ on the inside perimeter of the edges relative to the rest of the area. I explained to them I got the instructions from BW. He said they never heard of such a thing and, in his opinion, didn’t think it was the correct way for my particular repair. (As I read it the reason for the mashing was to prevent possible water penetration into the new seam if the new glass had not adhered correctly.) He asked me to fax it to him so he could see it for himself because it didn’t make sense to him.

Upon further discussion he suggested a much easier and simpler way that had been explained in detail in one of the manuals.

Well, there I was again with two expert but differing opinions and once again I had to decide what I thought was the right thing to do. How many times in my life has this happened? Too many. There are many different types of repairs of course. Fixing a small puncture or nick requires a different repairing technique than a major rip or crack several feet long. Also, location can be a determining factor. Is the damage on a relatively flat and un-stressed such as the topsides or on the keel, transom or on a chine?

In hindsight, and for that particular repair, using West’s method of just leaving the affected area intact would have been A LOT faster, easier and stronger, although maybe just marginally. It involved sawing along the jagged edges so they would not rest on top of each other, drilling (smallish) holes just through the hull in the area surrounding the damage and filling the holes with epoxy to cure. This would adhere the hull to the foam again. With that cured you then grind off the gelcoat and apply the applicable thickness of new glass over the larger area. I know I got some of this wrong but that’s the gist of it as I remember.

So, the bottom line of all of this for me is that you need to learn as much as possible before tackling these types of repairs. There doesn’t seem to be absolute right or wrong ways of repairs but some may be better than others.


Angryeel posted 11-12-2001 10:28 PM ET (US)     Profile for Angryeel  Send Email to Angryeel     
I have done some repair work on my 17' and have what may be an overly simplified bit of advice: look at a variety of methods of repair and then make an honest assesment of your ability to perform the various methods effectively along with what you have for tools and other recourses. I am sure of all the ways to fix your problem, which by the way does not sound that severe, there will be one way that you feel the most comfortable performing with the recourses you have at your disposal. As an example, have you ever read a repair manual for a modern vehichle? They give you great instructions; provided you are working in a shop stocked with all the specialty tools from the manufacturer. In other words, they do not tell you how to perform the task with tools that normal people have, like a ratchet set and some screw drivers and such. Instead, they recomend that you use "special suspension tool #17893" ect. What I am trying to say is that no matter what the "best" way to do the repair, the only one that will work is the one you are able to do properly. That said, I think most of the methods described above will work to fix your gouge; it does not sound like it is that bad.

PS, do not overlook a little marine filler covered with some fairing compound, a little primer and some gelcoat repair to fix the cosmetic issue. Just make sure you are dealing with dry foam.

bigz posted 11-13-2001 07:58 AM ET (US)     Profile for bigz    
Thank you Larry looking forward to reading it and offering an opinion.

Cvsa78, sounds like a minor repair, actually had a similar one on our '89 13 which was present when I bought her -- foam wasn't wet though --- I used a similar method West Sys describes, with some modifications I learned from doing work with a professional over the past two years.

I would let the foam dry probably just surface moisture unless you had not noticed it and boat sat in the water for a lengthy period of time. If this wasn't the case would suggest the West System Repair manual this repair is covered for a small "gash".

One of the problems as Arch and Angryeel alludes to is it is very difficult to try and advise a fix when each person has sort of their own terminology to describe the problem and conditions surrounding the problem. What is one persons "gash" might be another's "gouge", or tear to a rip, deep to shallow, etc etc. this is one reason to reference West Sys, MAAS, System 3 or even Whaler's repair manuals so that you the repair person have an idea of what your really faced with ---

I for one would much rather be using the boats than becoming an expert repairing them --- though basic knowledge is invaluable and can save you lots of money over time in lieu of having to take it to a professional shop.

Might add as Arch and Angryeelpointed out realize what your able to do and if beyond your scope leave it to a pro, in the long run will usually be more cost effective. Tom

cvsa78 posted 11-13-2001 08:36 AM ET (US)     Profile for cvsa78  Send Email to cvsa78     
I wanted to thank everyone for all thier valuable input. I'm moved to boat into the garage and flipped it over to make it easier to work on. I'll let you know how it works out.


Tom W Clark posted 11-13-2001 11:09 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
cvsa78, I'm glad you're going to try and repair it yourself. To answer your question, yes, you need the foam to be dry. If the foam was moistened with salt water, then it needs to be rinsed and dried.

bigz is right, there are lots of ways to make this repair. You could just go get yourself some MarineTex and trowel it in the hole, wait for it to kick, and then sand it smooth. Being on the bottom of the boat, nobody would ever see the patch.

But not all repair techniques are going to be equally effective, long lasting and good looking. Nor are all repair techniques going to cost the same. If economy isn't a consideration, then by all means have a shop repair the boat for you and be done with it.

But this doesn't sound like big deal at all. the term "Large Structural Repair" is Whaler's, not mine. In the context of the repair instructions, its definition is: a hole larger than a dime, with crushed foam. I should have made that clear; don't want to discourage you. If the foam is not crushed, then dispense with the foam rebuilding part of the instructions and proceed.

No matter what technique you decide to use, I don't think this is going to be a particularly onerous task. And no matter what technique you use, the basic steps are going to be the same: 1) remove the damaged portions. 2) replace with something to make it look like new.

The Whaler instructions sound remarkably straightforward and require no special tools and only polyester resin. I have no doubt epoxy will work as well but it will cost more. Not sure it's necessary. I have used both polyester resins and epoxies on my boats and both are equally easy to use. I frequently use epoxy in my trade and think it's great stuff. I have both epoxy and polyester resin sitting in my basement right now.

I also have a big slap of polyurethane foam that's been kicking around down there for the last 15 years. Perhaps I should offer it up to anybody who needs a piece for a repair.

lhg posted 11-13-2001 06:19 PM ET (US)     Profile for lhg    
As far as BW hull repairs, I'm siding with Boston Whaler instead of West System. It would seem logical to me that the inventors and manufacturers of the hulls would know more about repairing their boats than some Epoxy manufacturer. West's has a profit motive in selling their repair manual and products. BW only wants to see the boats properly repaired for satisfaction of their owners, and reputation.

There are only two engineering concepts in the BW hull design, that other brands don't require:

1. integrity and 360 degree continuous stress distribution within the "skin", particularly the outer skin.

2. Bond of the skin to the foam. There is nothing else that holds these hulls together, and is the basis for their legendary strength & rigidity.

BW's method, from what I can tell, is to accomplish both of these considerations, which is why the foam must be scraped out from underneath the damaged edge of the skin, with "mash" then inserted. The purpose of the "mash" is to grab the skin on both sides, so the new glass matting laid in can re-form a continuous structural skin. The comment about "doughnuts" is ridiculous, and shows a complete lack of understanding of the continuous skin concept. The intention is to duplicate the original construction as close as possible, and not to just glob in an epoxy patch, the way a car body would be repaired.

The question is, can a 40,000 bulldozer be driven on top of an 18 Outrage hull that has been repaired BW's way or West's way? I'll bet on the BW way.

triblet posted 11-13-2001 06:45 PM ET (US)     Profile for triblet  Send Email to triblet     
West System is not the same as West Marine.
However, West Marine sells West System. As
do other marine supply places.

Anybody got the story of the G. Bros. came
up with the West System name?


russellbailey posted 11-13-2001 06:53 PM ET (US)     Profile for russellbailey  Send Email to russellbailey     
Lots of good suggestions. Hopefully mine will add.

1. The Whaler instructions posted above assume you are using polyester (or possibly, but unlikely vinylester) resin, which will dissolve styrofoam. Epoxy will not. I wonder if epoxy was readily available when the instructions were written?

2. With resins, there are two kinds of bonds, which I'll call chemical and physical. When you lay the hull up originally and everything is wet, you get a chemical bond. For this task, any of the 3 resins work quite well and get good bond strength. Polyester is cheapest and used the most.

3. When you do a patch, you are getting a physical bond. For this, epoxy is far superior to polyester or vinylester.

Does it really matter when patching a Boston Whaler? I doubt it. What are the odds of a hard hit again in that spot? Except for an impact, the hulls on these boats are not highly stressed.

My boat patching experience comes from 'exotic' fabrics (carbon kevlar weave, S-glass, pure carbon,foam core) and epoxy on wildwater boats. Picture a stiff 17' canoe weighing 30 lbs that gets bashed on whitewater with two occupants - here things are highly stressed, and a polyester patch will quickly peel off and fail where epoxy will not.

Good luck.

lhg posted 11-13-2001 09:10 PM ET (US)     Profile for lhg    
BW says that polyester resin will not dissolve the polyurethane foam used in Whalers. Styrofoam (the blue stuff) is specifically not to be used.

Also, with the Whaler instructions you are working while everything is wet, specifically to get the chemical bond, like the original construction at the factory.

Draftsmanswife posted 11-14-2001 11:16 AM ET (US)     Profile for Draftsmanswife  Send Email to Draftsmanswife     
After chatting with my husband (BW draftsman for 12 years) about this issue, I have to agree with going with the factory reccomendations. No doubt they know how to fix them better that anyone!
dburton posted 11-14-2001 02:53 PM ET (US)     Profile for dburton  Send Email to dburton     
Last week I bought a 1976 13’ sport. She needs a lot of TLC to bring this lady back to the water. The boat needs fiberglass work on the bottom of the boat. I have followed this thread with interest. I have also read the West Systems books and have viewed their video tape. I am clear on how to fix a spot on a fairly flat section on the hull. My question is how to fix the keel and or the other small fins (lack of a better word). I have numerous nicks and other spots all along the protrusions in the hull.

I have 3 bad places (each about eight inches long) where the entire gel coat is gone and the blue fibers are showing. These spots are very firm and do not yield when pushed upon with my hand. The blue fibers themselves look intact.

I have one spot that is about six inches long where the fibers are frayed or gone. Only about two inches of this section is actually open to the foam. This part does yield when pushed.

Here are my questions:

1) On the places where the blue fibers are intact, can I simply epoxy over these adding no more glass matte or tape? Then Gel –coat over the top?

2) On the spot that is open to the foam (2inches long) and yields with pressure can I inject epoxy into the keel all along this spot and then build up the spot using epoxy and glass matte?

3) How important is finish shaping of the keel and other small fins? It seems difficult to me not to alter the shape of those protrusions.


Arch Autenreith posted 11-14-2001 11:26 PM ET (US)     Profile for Arch Autenreith  Send Email to Arch Autenreith     
Doug. In my opinion:

1) Yes
2) I'm not sure what you mean by injecting epoxy into the foam. Why not just glass over the exposed foam and 'build up' with matte and/or with filler as necessary?
3) Is the damage that extensive that you can't 'follow' the existing form? I'd like to see a picture. Can you email me a pic?

The keel on my Montauk was scraped nearly down to the foam in places from launching and retreiving from a badly designed system of rollers, bunks and guides.

I dragged the trailer out from under it, pulled it up on it's side, ground off about a 5 inch-wide swath of gelcoat and re-glassed with 4 inch-wide glass. I think it turned out perfectly. I didn't gelcoat as I will be putting on bottom paint this spring.

And I think the protusions you're talking about are the sponsoons. (I think that's what they're called. Now I'm not sure;))

Good luck getting your 13' sport back in the water! Let us know how it turns out.

dburton posted 11-15-2001 12:32 AM ET (US)     Profile for dburton  Send Email to dburton     

Thanks for your thoughts.

What I meant by injecting epoxy into the keel was I would drill holes into the keel (hopefully not through to the other side) and then inject epoxy into the holes using syringes. The purpose would be to create adhesion between the outer skin and the foam and to strengthen the keel in the area that yields to pressure. This step is an adaptation of the West System’s for delamination.

I’ve never done fiberglass work before. It seems straightforward enough on a smooth part of the hull. My concern is my ability to maintain the shape of keel and the sponsoons (I thought you spit into those). From your post you seem to have done an excellent job of forming the shape of the keel and the sponsoons. Hopefully when I get into it, it will be easier than I’m making it out to be just thinking about it.

I would be grateful if you looked at a picture. I will be a couple of weeks before I can send one. I hope to turn the boat over this weekend. My digital camera doesn’t offer the resolution that is needed to see what I’m talking about. So, it will take a week or two to take & scan a traditional photo.


Does anyone else have any thoughts or would like a picture of a pretty beat-up keel of a 13’?

Arch Autenreith posted 11-15-2001 09:04 AM ET (US)     Profile for Arch Autenreith  Send Email to Arch Autenreith     
Hey Doug.
I do understand the process of holes then filling with epoxy w/syringes but I thought you were going to drill holes in the exposed foam then fill and I didn't understand the logic of that. Now I do.
I'll await the pics. Even though you haven't done this before as you say and the learning curve will be steep I think you'll do a fine job. Some may feel a shop should do your repair but most of my jobs are better than shops! Lol. Seriously.

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